Design Guidance for Replacement Windows

These guides examine the energy use impacts of replacement windows for homes in hot, mixed and cold climates. They show the the impact of orientation, window area, and shading. The energy use has been calculated for various window design variations including 5 orientations (equal, north, east, south, and west), 3 glazing areas, 20 glazing types, and 5 shading conditions.

Providing views, light, and fresh air represent traditional window
functions that do not change fundamentally as new technologies are introduced and should be considered in the design process.

Efficient windows basics

Designing new homes can be a complex issue, but some straightforward principles and guidelines may help you set a solid foundation for window energy efficiency upon which you can further improve with careful design. Two of the most straightforward principles of selecting efficient windows are these:

Opportunities for Design Improvements

Energy-efficient windows offer benefits under diverse design conditions. Window performance can be improved by taking orientation, window area and shading into account. Fine-tuning your window selection to the houses conditions and optimizing these conditions where possible helps further cut heating and cooling demand. Besides long-term energy savings, these upfront opportunities may be available:

ENERGY STAR Homes recognition: High-performance design can allow homes to be recognized by the ENERGY STAR program. Many States and localities offer design help and/or incentives for ENERGY STAR homes.

Green building certification: Local and national green building programs recognize energy efficiency, including high-performance window design, as an important element of sustainable construction.